Phase 2 of the study is an observational cohort of all women who are eligible for initiation of lifelong antiretroviral therapy (following SA guidelines), from their second antenatal clinic visit until their first postpartum clinic visit (conducted within 7 days postpartum). This phase of the study will provide detailed description of ART initiation and antenatal follow-up in the population of women who will be involved in the postnatal component of the study, and be used to measure potential predictors of the primary outcome. At the second antenatal clinic visit, women from Phase 1 who are ART-eligible or who initiated ART during the pregnancy will be approached to complete Informed Consent #2, be interviewed with questionnaire on behavioral and psychosocial measures, and undergo phlebotomy. Women will complete another study measurement visit during the third trimester and again within 1 week postpartum (with study measurement visits timed to coincide with routine care appointments). At these visits, additional questionnaires and phlebotomy will be used to collect study measures.